Documentation: reset: describe new "--keep" option

diff --git a/sha1_name.c b/sha1_name.c
index 1739e9e61240c33a1e2bf110bbeeee111c380716..9215ad1d050c427b67124f4c5ca76e60e8e022f0 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -5,6 +5,7 @@
 #include "blob.h"
 #include "tree-walk.h"
 #include "refs.h"
+#include "remote.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -240,7 +241,8 @@ static int ambiguous_path(const char *path, int len)
 
 /*
  * *string and *len will only be substituted, and *string returned (for
- * later free()ing) if the string passed in is of the form @{-<n>}.
+ * later free()ing) if the string passed in is a magic short-hand form
+ * to name a branch.
  */
 static char *substitute_branch_name(const char **string, int *len)
 {
@@ -323,6 +325,20 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
        return logs_found;
 }
 
+static inline int upstream_mark(const char *string, int len)
+{
+       const char *suffix[] = { "@{upstream}", "@{u}" };
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(suffix); i++) {
+               int suffix_len = strlen(suffix[i]);
+               if (suffix_len <= len
+                   && !memcmp(string, suffix[i], suffix_len))
+                       return suffix_len;
+       }
+       return 0;
+}
+
 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
@@ -340,8 +356,10 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
        if (len && str[len-1] == '}') {
                for (at = len-2; at >= 0; at--) {
                        if (str[at] == '@' && str[at+1] == '{') {
-                               reflog_len = (len-1) - (at+2);
-                               len = at;
+                               if (!upstream_mark(str + at, len - at)) {
+                                       reflog_len = (len-1) - (at+2);
+                                       len = at;
+                               }
                                break;
                        }
                }
@@ -740,17 +758,10 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 }
 
 /*
- * This reads "@{-N}" syntax, finds the name of the Nth previous
- * branch we were on, and places the name of the branch in the given
- * buf and returns the number of characters parsed if successful.
- *
- * If the input is not of the accepted format, it returns a negative
- * number to signal an error.
- *
- * If the input was ok but there are not N branch switches in the
- * reflog, it returns 0.
+ * Parse @{-N} syntax, return the number of characters parsed
+ * if successful; otherwise signal an error with negative value.
  */
-int interpret_branch_name(const char *name, struct strbuf *buf)
+static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 {
        long nth;
        int i, retval;
@@ -836,6 +847,60 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
        return st;
 }
 
+/*
+ * This reads short-hand syntax that not only evaluates to a commit
+ * object name, but also can act as if the end user spelled the name
+ * of the branch from the command line.
+ *
+ * - "@{-N}" finds the name of the Nth previous branch we were on, and
+ *   places the name of the branch in the given buf and returns the
+ *   number of characters parsed if successful.
+ *
+ * - "<branch>@{upstream}" finds the name of the other ref that
+ *   <branch> is configured to merge with (missing <branch> defaults
+ *   to the current branch), and places the name of the branch in the
+ *   given buf and returns the number of characters parsed if
+ *   successful.
+ *
+ * If the input is not of the accepted format, it returns a negative
+ * number to signal an error.
+ *
+ * If the input was ok but there are not N branch switches in the
+ * reflog, it returns 0.
+ */
+int interpret_branch_name(const char *name, struct strbuf *buf)
+{
+       char *cp;
+       struct branch *upstream;
+       int namelen = strlen(name);
+       int len = interpret_nth_prior_checkout(name, buf);
+       int tmp_len;
+
+       if (!len)
+               return len; /* syntax Ok, not enough switches */
+       if (0 < len)
+               return len; /* consumed from the front */
+       cp = strchr(name, '@');
+       if (!cp)
+               return -1;
+       tmp_len = upstream_mark(cp, namelen - (cp - name));
+       if (!tmp_len)
+               return -1;
+       len = cp + tmp_len - name;
+       cp = xstrndup(name, cp - name);
+       upstream = branch_get(*cp ? cp : NULL);
+       if (!upstream
+           || !upstream->merge
+           || !upstream->merge[0]->dst)
+               return error("No upstream branch found for '%s'", cp);
+       free(cp);
+       cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
+       strbuf_reset(buf);
+       strbuf_addstr(buf, cp);
+       free(cp);
+       return len;
+}
+
 /*
  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
  * notably "xyz^" for "parent of xyz"